<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    var myImage = (function () {
        var imgNode = document.createElement('img');
        document.body.appendChild(imgNode);

        return {
            setSrc: function (src) {
                imgNode.src = src;
            }
        }
    })();

    var proxyImage = (function () {
        var img = new Image;
        img.onload = function () {
            myImage.setSrc(this.src);
        }
        return {
            setSrc: function (src) {
                myImage.setSrc('file:// /C:/Users/svenzeng/Desktop/loading.gif');
                img.src = src;
            }
        }
    })();

    proxyImage.setSrc('http://www.baobeihuijia.com/images/banner-01.jpg');
</script>
</body>
</html>